Aim: To study the sputum microbiology of patients admitted to a teaching hospital with acute exacerbations of chronic obstructive pulmonary disease (AECOPD) with concomitant pneumonia.
Methods: This was a retrospective study in a tertiary university hospital in Hong Kong. All episodes of AECOPD with pneumonia, patient demographics, length of stay, sputum culture and radiological results admitted in the first half of the year 2000 were retrieved from hospital records.
Results: There were 118 patients (91 male) with 150 episodes of AECOPD with concomitant pneumonia. The age of the patients was 74.8 +/- 10.0 years. Positive routine sputum culture was detected in 45.6% of the patients. Among these hospital admissions, 8.7, 4.0 and 12.0%, respectively, required intensive care unit admissions, mechanical ventilation and non-invasive positive pressure ventilation. Haemophilus influenzae was the commonest organism found in sputum (26.0%), followed by Pseudomonas aeruginosa (5.5%), Streptococcus pneumoniae (3.4%), and Moraxella catarrhalis (3.4%). Mycobacterium tuberculosis was found in 1.5% of the admissions. The presence of P. aeruginosa in sputum was associated with a longer hospital length of stay (9.1 +/- 3.1 vs. 7.1 +/- 4.2 days, P = 0.03).
Conclusion: In contrast to most other studies reporting S. pneumoniae as the most likely bacterial pathogen, H. influenzae was the commonest bacterium isolated in sputum in our patients with AECOPD and concomitant pneumonia.